The Justice Department this week lost an appeal that would have allowed the government to use cell phone data to track your location without having probable cause. A judge in the U.S. District Court for the Western District of Pennsylvania ruled that such tracking could violate the Fourth Amendment against unreasonable search and seizure (yeah, there’s a reason you learn about these documents in school), and said law enforcement officials need to show probable cause before getting access to such records. Those records show which cell phone towers were pinged by a suspect’s phone, and give a reasonable idea as to where a person is.